Battery (not hybrid battery) went bad and made it do crazy stuff and cut off?

Okay, my battery terminal was loose, so some dummies took a piece of a beer can put it around it to make it fit tighter. Well, after time that corroded to the point it had the post of the battery crumbling. The car would cut off while driving and wouldn’t start (hazard lifts wide even cow on) so I get out bag on it and bam bag running. So, I eventually replaced my battery in the car. It did fine for about a week and then started doing the same thing it would throw all my hybrid codes. It would cut off I felt like the terminal cable or wiring or whatever shit have been replaced but since I’m a girl they won’t listen to me. I’ll take it to a mechanic he’s like we need to change the spark plugs the time and bills war out the time a bit needs to be changed and I understand because it is older vehicle. It probably is time for all that to be done but that I truly feel is not it was causing my car to run terrible, after getting a new battery it is a little better but not completely so this mechanic changed three of my spark plugs and said that it’s still running the same. The timing belt is not broken. I’m sure it is worn and I’m sure it is time to be changed but is it just a coincidence that the battery having a bang on it made the car start back up I think it has something to do with the wiring or the battery issue not the Hybrid battery the reg battery.